Title

Firefox must be configured so that DNS over HTTPS is disabled. (Cat II impact)

Discussion

DNS over HTTPS has generally not been adopted in the DoD. DNS is tightly controlled. It is detrimental for applications to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Applications are capable of providing a wide variety of functions and services. Some of the functions and services, provided by default, may not be necessary to support essential organizational operations (e.g., key missions, functions). Examples of non-essential capabilities include, but are not limited to, advertising software or browser plug-ins not related to requirements or providing a wide array of functionality not required for every mission, but cannot be disabled.

Check Content

Type "about:policies" in the browser address bar. If "DNSOverHTTPS" is not displayed under Policy Name or the Policy Value does not have "Enabled" with a value of "false", this is a finding.

Fix Text

Windows group policy: 1. Open the group policy editor tool with "gpedit.msc". 2. Navigate to Policy Path: Computer Configuration\Administrative Templates\Mozilla\Firefox\DNS Over HTTPS Policy Name: Enabled Policy State: Disabled macOS "plist" file: <key>DNSOverHTTPS</key> <dict> <key>Enabled</key> <false/> Linux "policies.json" file: Add the following in the policies section: "DNSOverHTTPS": {"Enabled": false}

Additional Identifiers

Rule ID: SV-251577r879587_rule

Vulnerability ID: V-251577

Group Title: SRG-APP-000141

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.